Client distinguish between eye and mob for drawing, context menu, and verbs

[Ruzihm]

Adds a network message sent from the server to client to notify of mob/eye updates (currently, the client uses the attached entity which is ambiguous). I wasn't sure of a better way to accomplish this but am looking for feedback.

The client then uses this info to distinguish between eye/mob for context menu, drawing, and verbs.

Closes #1581